One type of electrical extension cord, commonly known as a power strip, generally comprises an elongate box-like housing having a row of plug-receiving receptacles formed therein, an on/off switch, and a single power cord which is connectable to a standard (e.g., nominal 110 volt) wall outlet. The power cord is typically plugged into the wall power outlet, to energize the power strip. Thereafter, a plurality of devices may be plugged into, the various plug receiving receptacles of the power strip. When the on/off switch of the power strip is turned to its "on" position, current will flow to the plug-receiving receptacles and any devices which are plugged into the power strip will become energized. Conversely, when the on/off switch is placed in its "off" position, devices which are plugged into the electrical power strip will become de-energized. Some of the electrical power strips of the prior art have included resetable circuit breakers and/or power surge protectors.
When using modern electrical devices and appliances, it is often desirable to cause a plurality of secondary devices to become energized and de-energized concurrently with a primary device. For example, when using a computer, it is sometimes desirable to energize/de-energize a group of secondary or peripheral devices concurrently with the computer. Examples of such secondary devices which may be powered externally of the computer include modems, monitors, printers, plotters, scanners, compact disk drives, hard disk drives, tape back-up drives, mice, digitizing tablets, etc.
In some instances, it has been common practice for the user of the computer to plug all of the desired secondary or peripheral devices into an electrical power strip of the above-described character such that, after the computer has been energized, the user may utilize the off/on switch of the power strip to simultaneously energize all of the computer peripheral devices which are plugged into the power strip. However, in many instances, the power strip must be located in an obscured position (e.g., on the floor behind or beneath an item of furniture) so as not to be easily accessible by the operator when it is desired to utilize the off/on switch of the power strip. In such cases, it may be necessary to leave the off/on switch of the power strip in the "on" position, and to laboriously turn each of the secondary or peripheral devices on an off independently, rather than utilizing the single on/off switch of the power strip to effect simultaneous energization and deenergization of the secondary devices.
In some types of primary devices (e.g., personal computers, stereo receivers/amplifiers) one or more power output jacks may be provided on the main device to permit one or more secondary or peripheral devices to be plugged directly into such power output jacks such that the secondary or peripheral device(s) become energized simultaneously with the main device. However, the current draw caused by some types of secondary or peripheral devices may result in over heating or overloading of the internal circuitry of the main device. Thus, in many instances, it is desirable to plug the secondary or peripheral devices into an independent electrical current source (e.g., a separate wall outlet) rather than plugging such secondary or peripheral devices directly into power output jacks formed in the main device. Electrical power strips of the foregoing character are frequently used for this purpose, but are subject to the limitations and difficulties of use described hereabove.
For numerous reasons, including technical considerations which may necessitate substantially simultaneous energization/de-energization of a plurality of secondary devices (e.g., computer peripheral devices) with a single primary device (e.g., a computer), there exists a need in the art for an improved electrical power strip which will automatically energize and de-energize plurality of devices which are plugged into the strip, upon receiving an electrical signal from the primary device, without the need for manual actuation of a switch on the electrical strip by the user.